One vertex per element, one color per generator, with an edge from x to x·s.
(2,6)(7,8)(9,10)(11,13)(12,16)(14,18)(15,17)(19,21)(20,23)(22,24)(25,26,30,28)(27,31,33,34)(29,32,37,36)(35,38,39,40)(1,2)(3,7)(4,8)(5,6)(9,11,15,12)(10,16,17,13)(14,19,22,20)(18,23,24,21)(25,27)(26,31)(28,34)(29,35)(30,33)(32,38)(36,40)(37,39)(1,3,5,4)(2,7,6,8)(10,17)(11,12)(14,22)(21,23)(27,33)(31,34)(35,39)(38,40)(1,3,5,4)(2,7,6,8)(9,12,15,11)(10,16,17,13)(14,20,22,19)(18,23,24,21)(25,28,30,26)(27,34,33,31)(29,32,37,36)(35,38,39,40)(1,3,5,4)(2,7,6,8)(9,13,15,16)(10,12,17,11)(14,21,22,23)(18,20,24,19)(25,29)(26,32)(27,35)(28,36)(30,37)(31,38)(33,39)(34,40)(1,4,5,3)(2,8,6,7)(9,14)(10,18)(11,19)(12,20)(13,21)(15,22)(16,23)(17,24)(25,27)(26,31)(28,34)(29,35)(30,33)(32,38)(36,40)(37,39)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.